what is Chelating agent?

Those compounds which form a soluble complex with cations especially with metals such as Zinc, Iron, Calcium e.t.c. are called chelating agents or chelator. Chelator also present in soil derived from phenolic compounds present in decaying ligning from wood (Humus). But its quantity is insufficient for soil fertilization. Most common used chelator is EDTA (Ethylene diamine tetraacetic acid).